Mechanically matching components, which are fitted together in pairs, are well known in various fields. For example, in an injector such as a fuel injector, an injector needle and an injector body form a matching pair; in a piston pump, a piston and a cylinder form a matching pair; etc. The two components of a matching pair have matching portions which are to be fitted together with a certain fit tolerance or a gap between them. The accuracy of the fit tolerance should be controlled precisely for the correct function of the matching pair. It is known that in most cases the two components of a matching pair are machined individually and have particular dimensional tolerances at their matching portions. It is difficult to ensure a correct fit tolerance or a correct gap to be obtained from the combination of the dimensional tolerances of the matching portions.
For example, when manufacturing fuel injectors, nozzle bodies and nozzle needles, after grinding, are graded based on the dimensional precision of their matching portions, so that the nozzle bodies and the nozzle needles, which meet the fit tolerance requirement, are fitted together. For example, for nozzle bodies with the inner diameter of their matching portions having dimensional tolerances falling into a certain range, only the nozzle needles with the outer diameter of their corresponding matching portions having dimensional tolerances falling into a corresponding range can be used. That is to say, other nozzle needles with the outer diameter of their corresponding matching portions having dimensional tolerances falling out of the corresponding range cannot be used, and thus should be stored as inventory to be used with other nozzle bodies which are suitable for them. It can be seen that, for manufacturing fuel injectors as well as other devices with mechanically matching components in this way, a grading step has to be carried out. In addition, for achieving correct fitting with high probability, each type of nozzle needles should have 12 to 18 grades. This significantly increases the material cost, the manufacturing cost and the inventory cost, especially for coated needles for common rail injection systems. Even so, it still cannot ensure each time a successful fitting.
It is known that in common rail injector manufacturing field, a match grinding process is adopted which may alleviate the above problems. In a match grinding process, a valve body is manufactured first. The inner diameter of the matching portion of the valve body has a certain dimensional tolerance after grinding. Then, the inner diameter is pneumatically measured. Based on the measurement, the outer diameter of a matching valve needle is adaptively ground. In this way, the valve needle is suitable for the valve body, and no redundant valve needles will be created. However, in an injector assembled in this way, the fit clearance or guide clearance between the valve body and the valve needle may have a manufacturing tolerance larger than that required by the injector nozzle.
In recent years, ultrashort pulse lasers of femtosecond level have been used for laser ablation. As an example, Titansaphir-laser is used in cold material ablation, in which the removed material is transformed directly from solid state into gas state. No heat affected zone is found in the material near the ablation area. Lasers for this purpose are commercially available.
It is known that laser honing has been used for forming a running surface of a cylinder of an internal combustion engine.
It is also known to use ultrashort pulse lasers for manufacturing for example HDEVs, such as perforated injection disks. However, those lasers are psec-lasers, which cannot perform cold ablation. An object of the present invention is to overcome the above shortages existed in the prior art by providing an system and method which can manufacture mechanically matching components, such as injector bodies and injector needles of fuel injectors, in a more efficient way and with a lower inventory.